The present invention is directed to the field of sprayer systems, particularly those of the type used to produce more than one spray pattern, e.g. high volume, low pressure (HVLP) paint sprayers that use air jets to deform a circular spray pattern into a flat "fan" spray pattern.
A typical paint sprayer includes a sprayer nozzle that disperses a diverging conical spray envelope of paint for producing a circular pattern. Typical sprayers also include an aircap for alternately admitting the conical spray or deforming it into a fan pattern. The aircap includes spray shaping passages formed in wings of the aircap, on either side of the conical spray. These passages direct pressurized air from within the sprayer toward the conical spray, altering the shape of the conical spray to flatten it into a fan pattern.
The round pattern is selectively restored by shutting off the spray shaping passages. This is commonly accomplished by providing a rotatable aircap which is movable between two positions. In the first position, the spray shaping passages are in registration with corresponding openings in the sprayer, to admit pressurized air to the aircap shaping passages. The aircap can then be rotated to a second position where the spray shaping passages are blocked, thereby discontinuing airflow. However, this shut-off condition restricts the flow of air through the sprayer system, thus creating an increase in back pressure and motor speed (i.e. RPMs). This increases heat in the motor, resulting in additional wear and tear and thereby reducing the expected service life of the motor, and increases heat in the air hose, thus reducing its structural integrity.